Spelling is just a click away – a user-centered brain-computer interface including auto-calibration and predictive text entry

• Main Authors: Tobias eKaufmann, Stefan eVölker, Laura eGunesch, Andrea eKübler
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2012-05-01
• Series: Frontiers in Neuroscience
• Subjects: Brain-computer interface; user-centred; auto-calibration; predictive text entry; P300-Speller
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fnins.2012.00072/full

Brain Computer Interfaces (BCI) based on event-related potentials (ERP) allow for selection of characters from a visually presented character-matrix and thus provide a communication channel for users with neurodegenerative disease. Although they have been topic of research for more than 20 years and were multiply proven to be a reliable communication method, BCIs are almost exclusively used in experimental settings, handled by qualified experts. This study investigates if ERP-BCIs can be handled independently by laymen without expert interference, which is inevitable for establishing BCIs in end-user’s daily life situations. Furthermore we compared the classic character-by-character text entry against a predictive text entry (PTE) that directly incorporates predictive text into the character matrix. N=19 BCI novices handled a user-centred ERP-BCI application on their own without expert interference. The software individually adjusted classifier weights and control parameters in the background, invisible to the user (auto-calibration). All participants were able to operate the software on their own and to twice correctly spell a sentence with the auto-calibrated classifier (once with PTE, once without). Our PTE increased spelling speed and importantly did not reduce accuracy. In sum, this study demonstrates feasibility of auto-calibrating ERP-BCI use, independently by laymen and the strong benefit of integrating predictive text directly into the character-matrix.